1. Field of the Invention
This invention relates to video processing.
2. Description of the Prior Art
Video surveillance systems generally use video cameras at fixed spatial positions to generate video signals representing a scene under surveillance.
This type of system generates a large amount of video data, particularly when multiple cameras are used. Previously, two main solutions have been used to deal with this quantity of data.
One previously proposed solution is to store everything, which is to say that the video signal from each of the cameras is stored, generally in a rolling storage arrangement holding (for example) the preceding seven days of material. This means that video material relating to an incident can be obtained from the stored material, if the incident is discovered before the storage medium is overwritten by more recent video material.
Another previously proposed solution is to have a human operator view one or more video displays in real time, watching for incidents or other points of interest. This has the drawback that it is easy for a human operator not to notice changes in an image. These failures can be caused by a number of factors including external distraction, boredom and tiredness, or through limitations of the human psycho visual system such as so-called change blindness or inattention blindness. Here, change blindness is a phenomenon by which a human observer fails to spot even large changes in an image, if the change occurs at the same time as another visual disruption such as a saccadic eye movement, a blink, or a brief obscuration of the image.
It is an object of the present invention to provide improved techniques for video processing.